Control of paratuberculosis in five cattle farms by serological tests and faecal culture during the period 1990-1999

In the Slovak Republic, clinical paratuberculosis was detected for the first time in two cows in the farm NT in 1989. Gradually the disease spread to another four farms: M, HJ, H, and C, where there were 1 490 cows, 1 100 calves and 1 300 heifers. The introduction of Mycobacterium avium subspecies paratuberculosis to these farms was most probably due to the importation of 60 Holstein heifers from Denmark to farm NT in the late 1970s. In the mid-1980s, because of common housing with apparently healthy heifers, the remaining four free herds also became infected with paratuberculosis. In 1990, an eradication programme against paratuberculosis was established. In the first stage (during 1990-1992) of the programme all animals older than 18 months were examined by three serological tests: AGID (agar-gel-immunodiffusion), CFT (complement fixation test) and ELISA. Animals with repeatedly positive serological results were culled from the herd including clinically suspect animals. In the second stage (from 1992) serological tests were supplemented by two parallel faecal cultures per year. In 1990, the incidence of clinical paratuberculosis among the five farms varied (M - 4.1%, HJ 1.5%, H - 0%, C - 0% and NT - 0.5%). Cases of infection (n = 528) were divided into three groups: Ist without clinical signs and few CFU in faeces and/or gastrointestinal tract (60.8%)